1: /* arping/src/findif_linux.c
2: *
3: * Copyright (C) 2000-2014 Thomas Habets <thomas@habets.se>
4: *
5: * This program is free software; you can redistribute it and/or modify
6: * it under the terms of the GNU General Public License as published by
7: * the Free Software Foundation; either version 2 of the License, or
8: * (at your option) any later version.
9: *
10: * This program is distributed in the hope that it will be useful,
11: * but WITHOUT ANY WARRANTY; without even the implied warranty of
12: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13: * GNU General Public License for more details.
14: *
15: * You should have received a copy of the GNU General Public License along
16: * with this program; if not, write to the Free Software Foundation, Inc.,
17: * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
18: */
19: /**
20: * Fallback to ugly solution. This should not actually be used, as
21: * modern systems have getifaddrs().
22: */
23: #if HAVE_CONFIG_H
24: #include "config.h"
25: #endif
26:
27: #include <stdio.h>
28: #include <string.h>
29:
30: #if HAVE_LIBNET_H
31: #include <libnet.h>
32: #endif
33:
34: #include "arping.h"
35:
36: #error "This code should never be chosen. If you just want to use it then uncomment this error line"
37:
38: /**
39: * WARNING: non-reentrant
40: */
41: const char *
42: arping_lookupdev(uint32_t srcip,
43: uint32_t dstip,
44: char *ebuf)
45: {
46: FILE *f = NULL;
47: static char buf[1024];
48: char buf1[1024];
49: char buf2[1024];
50: char *p,*p2;
51: int n;
52:
53: *ebuf = 0;
54:
55: do_libnet_init(NULL, 0);
56: libnet_addr2name4_r(dstip,0,buf2,1024);
57: libnet_addr2name4_r(srcip,0,buf1,1024);
58:
59: /*
60: * Construct and run command
61: */
62: snprintf(buf, 1023, "/sbin/ip route get %s from %s 2>&1",
63: buf2, buf1);
64: if (!(f = popen(buf, "r"))) {
65: snprintf(ebuf, LIBNET_ERRBUF_SIZE,
66: "popen(/sbin/ip): %s", strerror(errno));
67: goto failed;
68: }
69: if (0>(n = fread(buf, 1, sizeof(buf)-1, f))) {
70: snprintf(ebuf, LIBNET_ERRBUF_SIZE,
71: "fread(/sbin/ip): %s", strerror(errno));
72: goto failed;
73: }
74: buf[n] = 0;
75: if (-1 == pclose(f)) {
76: snprintf(ebuf, LIBNET_ERRBUF_SIZE,
77: "pclose(/sbin/ip): %s", strerror(errno));
78: goto failed;
79: }
80: f = NULL;
81:
82: /*
83: * Parse interface name
84: */
85: const char* head = "dev ";
86: p = strstr(buf, head);
87: if (!p) {
88: if (verbose) {
89: printf("arping: /sbin/ip output: %s\n", buf);
90: }
91: snprintf(ebuf, LIBNET_ERRBUF_SIZE,
92: "\"dev \" not found in /sbin/ip output.");
93: goto failed;
94: }
95:
96: p += strlen(head);
97:
98: p2 = strchr(p, ' ');
99: if (!p2) {
100: if (verbose) {
101: printf("arping: /sbin/ip output: %s\n", buf);
102: }
103: snprintf(ebuf, LIBNET_ERRBUF_SIZE,
104: "interface not found in /sbin/ip output.");
105: goto failed;
106: }
107: *p2 = 0;
108: return p;
109: failed:
110: if (f) {
111: pclose(f);
112: }
113: return NULL;
114: }
115: /* ---- Emacs Variables ----
116: * Local Variables:
117: * c-basic-offset: 8
118: * indent-tabs-mode: nil
119: * End:
120: */
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